Seven new bis(dehydrobenzo[18]annuleno)benzenes (bis[18]DBAs) 1â7 functionalized with electron-donating dibutylamino groups and/or accepting nitro groups at various positions along the peripheries of the chromophores have been prepared. The effects of varying the donor/acceptor charge transfer pathways, chromophore lengths and molecular symmetries upon the optical band gaps are studied using UVâvisible spectroscopy, and structureâproperty correlations are identified. It is found that bis[18]DBAs possessing donorâÏâdonor and acceptorâÏâacceptor pathways exhibit the smallest band gaps, especially when an acceptorâÏâacceptor pathway is situated along the longest chromophore length in the molecule. The all-donor species 1 is also found to exhibit efficient fluorescence with dramatic solvatochromism. The results may have value to the rational design of future NLO/TPA device components.
我们制备了七种新的双(脱氢苯并[18]
环戊烯)苯(双[18]
DBAs)1â7,它们在发色团外围的不同位置上具有电子捐赠的二丁基
氨基和/或接受的硝基官能团。利用紫外可见光谱法研究了不同的供体/受体电荷转移途径、发色团长度和分子对称性对光带隙的影响,并确定了结构与性质的相关性。研究发现,具有供体-受体和受体-受体途径的双[18]
DBA 具有最小的带隙,尤其是当受体-受体途径位于分子中最长的发色团长度时。此外,还发现全供体物种 1 具有高效荧光和显著的溶解变色作用。这些结果可能对合理设计未来的 NLO/
TPA 器件组件具有重要价值。